diff --git a/nodehierarchy.module b/nodehierarchy.module
index 006a431..d64513c 100644
--- a/nodehierarchy.module
+++ b/nodehierarchy.module
@@ -724,7 +724,7 @@ function _nodehierarchy_save_node(&$node) {
     }
 
     // If the node type cannot be a parent, and has no parent itself, then do not save a link.
-    if ($node->nodehierarchy_menu_links[$i]['remove']) {
+    if (isset($node->nodehierarchy_menu_links[$i]['remove'])) {
 
       // We can only delete menu links that don't have children associated with them.
       if (!_nodehierarchy_get_children_count_plid($node->nodehierarchy_menu_links[$i]['mlid'])) {
diff --git a/nodehierarchy_views/nodehierarchy_views.module b/nodehierarchy_views/nodehierarchy_views.module
index cac186c..842f4e0 100644
--- a/nodehierarchy_views/nodehierarchy_views.module
+++ b/nodehierarchy_views/nodehierarchy_views.module
@@ -271,7 +271,7 @@ function _nodehierarchy_views_view_options() {
 function _nodehierarchy_views_is_nh_view($view, $display = 'default') {
   $view->set_display($display);
   $view->build($display);
-  $arg = reset($args = (array) $view->argument);
+  $arg = ((array) $view->argument !== array()) ? reset($view->argument) : FALSE;
   if (!empty($arg->table) && ($arg->table == "nh_parent" || $arg->table == "nh_ancestor")) {
     return TRUE;
   }
diff --git a/nodehierarchy_widgets/nodehierarchy_widgets.module b/nodehierarchy_widgets/nodehierarchy_widgets.module
index 3568f20..615d703 100644
--- a/nodehierarchy_widgets/nodehierarchy_widgets.module
+++ b/nodehierarchy_widgets/nodehierarchy_widgets.module
@@ -163,8 +163,10 @@ function _nodehierarchy_widgets_autocomplete_parent_validate($element, &$form_st
     if (!empty($matches)) {
       // Explicit [nid:n].
       list(, $title, $nid) = $matches;
-      if ($err = _nodehierarchy_widgets_is_invalid_parent($nid, $form_state['values']['nid'], $form_state['values']['type'])) {
-        form_error($element, $err);
+      if (isset($form_state['values']['nid'])) {
+        if ($err = _nodehierarchy_widgets_is_invalid_parent($nid, $form_state['values']['nid'], $form_state['values']['type'])) {
+          form_error($element, $err);
+        }
       }
     }
     else {